To briefly add to the above writeup, in the U.S., Mexican restaurants or small fast food joints often sell horchata. It is most commonly found next to OLE! pina colada and that sweet orangey drink they call Bang. Or Orange Bang or something. As underaged (for drinking legally in California) young'uns, my friends and I often drowned our sorrows in large styrofoam cups of horchata on the rocks for 99 cents a round.

a horchata recipe

1 cup long grain white rice
2 cups skinless (and boneless) almonds OPTIONAL
1-inch stick canela or other cinnamon
8 cups water
1/2 cup sugar
1/4 teaspoon vanilla
Ice cubes

Wash and drain rice. Using a spice grinder (or a blender), grind the rice for a few minutes until fine; combine with the almonds (if using) and cinnamon bark. Add 3 1/2 cups water and let sit overnight, covered. Blend rice mixture until smooth using a blender. Add 2 1/2 cups of water and continue blending. Add and dissolve sugar and add vanilla extract. Strain horchata into a bowl first using a metal strainer and then a double layer of cheesecloth. (Don't skimp on these steps or the drink will come out tasting like chalk); finish with up to an additional 2 cups of water until it achieves a milky consistency. Serve and enjoy over ice (see recipe for ice).